Device for supporting a guitar (1) or another string instrument, with a support (2) which is fastened on its upper part to a guitar body (9) in a lockable hinge (4). In an unfolded position the support (2) creates an angle at approximately 45° to the length axis through the guitar body (9), in such manner that the guitar can rest on the support (2). When mounted on an electric guitar the support is placed in grooves at the back of the guitar, and can be pivoted from the guitar body when the locking mechanism is released.